ScriptBot 0.0.2 has just been released. While still in alpha stage, it's already fully functional and Bug Free(tm) :P
ScriptBot is a scriptable IRC bot written in java. Based on PircBot and BSF, it allows to fully customize the bot's behaviour by editing script files in the scripting language of your choice.
Scripts are organized into modules, which can be loaded and unloaded as a whole. A module is constituted of a) the module start script b) command handlers and c) event handlers.
Other notable features include: automatic persistence for any POJO (plain old java object) utilizing XStream ( http://xstream.codehaus.org/ ), builtin user and group managment and customizable implementation configuration through the use of spring ( http://springframework.org/ ).
Sourceforge.net project page: http://sf.net/projects/scriptbot
Download: http://sourceforge.net/project/showfiles.php?group_id=63543&package_id=219734
Wiki: http://scriptbot.jawe.net/